What Causes Sterility in Frogs

Image Source

Most of us learn about basic frog reproduction in grade school. In the rain forest, red-eyed tree frogs usually mate on a leaf. Frogs lay their eggs in water, which are hatched into tadpoles and eventually grow as frogs. About fifty percent of all frogs follow these steps. There are instances when frogs cannot reproduce, causing sterility.

In this post, you’ll learn about frog reproduction and the min causes of sterility.

Frog Reproduction

Here are rules of thumb that you need to know about frog reproduction.

Frogs reproduce sexually and also hatch from eggs.

Fertilization of eggs happens outside the body of the female rather than inside.

Females release their eggs and males release their sperm at the same time.

Male and female frogs get into a mating posture, which is referred to as amplexus, wherein the male climbs onto the back of the female and clasps the forelegs around the female frog’s middle.

Frogs usually stay in amplexus for several hours or a couple of days, and the female releases one or several hundred eggs.

It is easy to determine male from female frogs. In fact, many frog species are described as sexually dimorphic. It means that there are color and other physical differences between male and female frogs. In some species, male and female frogs are hard to determine. Male frogs in this species usually create a release call when they are clasped by another male frog. During the mating season, release calls are used to decipher male from female frogs.

Sterility in Frogs

Many reproductive disorders, which involve the increased occurrence of the intersex gonads and damage gametocyte growth, have been claimed in wild aquatic organisms and in the contaminated sites within the world. The study of some common potential reasons for these kinds of reproductive disorders has mostly paid attention to the environmental chemicals that interfere with estrogen. The progesterone gesture has gained very small attention regards as a main target of the disruption. However, it is the main key to a regulatory alley in the growth as well as the function of the female reproductive organs.

The synthetic progesterone is also known as the Progestins are medicines that usually used in a human as well as veterinary medicine, in contraceptives, and also in other hormonal therapies. These combinations are let out into an aquatic surrounding from the sewage medical care plants, medicine industries, and in the agricultural places like the farm animal waste.

Additional details on the result of the progestins on the aquatic animals are required to assess the danger in surroundings that effects these kinds of compounds. Progesterone is involved at a number of stages of the oogenesis. However, the process of its action remains to be as clarified. The progestogens have been proposed to be part of the following:

  • The earliest period of oogenesis as well as the follicular congregation of mammals
  • Becomes the vitellogenesis in the amphibians, reptiles as well as in fish
  • Encouraging the final occurring of oocyte maturation.

But still, the genuine physiological prompt of the reopening of meiosis in vivo looks like to be as androgens. Since the progesterone is readily turned to androgen by the stimulant in the oocyte, the engaging role of progesterone in the last oocyte discharge seen in vitro might become the substrate for the production of androgen.

The outstanding model organism is the Xenopus tropicalis, which was used for the study of reproductive as well as the endocrine toxicity for so many reasons.

  1. Xenopus tropicalis is very delicate regarding endocrine-disrupting compounds.
  2. Xenopus tropicalis has a relatively short time, which is 6 months; it provides a unique chance, unlike with the other species of frog.
  3. It is closely-like to Xenopus laevis and a well-defined model for the used for studies regarding oocyte maturation. Yet, another cause must be that organization and parts of the hypothalamus-pituitary-gonadal alliance are just the same for those like in mammals.
  4. Xenopus tropicalis is very fit to be the model in the experimental in some aquatic toxicology because x.tropicalis is a water-dwelling kind for the rest of their life.

Most of the amphibians, as well as the terrestrial kinds, are bred in the water that might be nearby to be vulnerable to a water-borne chemical in the course of their egg maturation cycle. However, the vulnerability setting in the latest research is somehow ecologically related.

The essence of the main intention of the latest study is to characterize the progestogenic effects on the full stage of oogenesis in the frogs and to regulate the amphibians’ reactiveness to the environmental progestogenic compounds regarding the reproducing-related reaction in females. The female Xenopus tropicalis were vulnerable to LNG with the environment water for about 7 up to 28 days after their full stage of oogenesis that includes the early cycle of meiosis as well as the complex of reproductive organs, and the subordinate characteristics of sex have been also analyzed.

It became visible to the frog that they are very tactful to progestogens. Progestogens are a type of medication that is released into the surroundings. The main subject to an abnormal ovarian and oviduct growth are the female tadpoles that usually swim in water that contains particular progestogen levonorgestrel. This might be the result of adult sterility. This becomes visible by a new study administrate at Uppsala University and issued in the journal named Aquatic Toxicology.

Irreversible Effects

Image Source

Almost all of the medicines that the humans are usually consumed are released from the surroundings via sewage systems. The progestogens are endocrine gland preparations that are usually used in some contraceptives, cure in cancer, and in the hormone substitute therapy for menopausal irritation. There are divergent kinds of progestogens that have been recognized in waterways in different countries.

The associate professor named Cecelia Berg and the student of doctoral named Moa Kvarnryd at the Department of Environmental Toxicology at the University of Uppsala have exhibited that the levonorgestrel can commonly cause sterility in female frogs. However, during absorption, it is not much higher than those that have been measured in the surroundings. This kind of research group is to the extent of MistraPharma, one of the world’s biggest research networks that central point on every pharmaceutical as well as the environment.

The female tadpoles that commonly swam in the water, which contains a low congregation of the levonorgestrel, shows a bigger part regarding the immature ovarian egg cells as well as lacking oviducts can be, entailing sterility. The West African clawed frog, also known as the Xenopus Tropicalis act as the main model organism. This is commonly done during the tadpole period that usually the development of every frog reproductive organs starts.

The procedure is presided over by the hormone structure. The discovery emphasizes the significance of studying how might be the pharmaceuticals can have an effect on most animals in the environment. This is one of the main purposes of MistraPharma. Their studies manifest that the pharmaceuticals other than the estrogen can become the usual reason for the permanent damage to the aquatic animals that usually unprotected during their early life periods.

When you are experiencing a hard time about breeding your frogs, it might be because of the water that they were nurtured during when they are tadpoles. There is research that recently published in the scientific journal named Aquatic Toxicology recommends that the frogs are very sensitive regarding progestogens, which are hormones that usually extend to appear as a surroundings contaminants. Sometimes these also used as a by-product in human therapeutics.

A tadpole female frog that resides in the water, which contains the lowest level of concentrations of the levonorgestrel, shows to be a greater part of being an immature ovarian egg cell. They are also considered as no oviducts, which means that they are sterile because they have the need for this vital anatomical element of their reproductive system.

Potential Impact

The probability of danger to the wild frog populations is very clear. Progestogen-Induced infertility might lead to an unexpected or a dramatic fall down regarding the success of the reproductive in the frog population or, certainly, the species for threatening to its survival. Actually, by the time comes that the reason for the complication is finally discovered, it might actually become too late to diverse the common effects.

This is mainly because the physical has an influence on the female tadpoles that have been sterilized because of its exposure to progestogens. In this situation, it cannot be reversed. The best long-term defense to protect is for the continuing keep track of the progestogen levels in the waterways that commonly become polluted with these kinds of hormones.


There are many reasons why frogs become sterile, such as environmental and chemical factors. Also, exposure to progestogens may cause sterility among frogs. Most of the metabolites of a lot of medicines that people are commonly taking are still come into the environment beyond the sewage systems. Various kinds of progestogens have so far been recognized in a waterway in the most number of countries. That’s why tracking the progestogen levels of frogs should be carried out.

What Beta Carotene Does to Your Lizard

Tortoise Health Conditions: Guide for Keepers