Function of the pineal gland in seasonal birth control in some animals
The pineal gland is just a non-functional degenerative part, but several findings in recent years suggest that it plays an important role in the control of sexual activity and reproduction.
Since the existence of the pineal gland is known, many of its functions have been attributed to it, including (1) enhancing sex drive, (2) suppressing inflammation, (3) promoting sleep. sleep, (4) emotional enhancement, (5) longevity glue (maybe 10 to 25%). It is also likened to the third eye on the head in some lower animals. Some physiologists think the gland is just a degenerative, non-functional part, but some findings in recent years suggest that it plays an important role in the control of sexual activity and reproduction.
Now, after many years of research, it has emerged that the pineal gland does not play a really important role in controlling sexual activity and reproduction. In animals whose seasonal reproductive cycles are removed or the blood vessels to the pineal gland are blocked, the reproductive stages are absent. In these animals, spawning occurs during certain times of the year (usually spring or summer), giving the young the best chance of survival. The mechanism of this process is not very clear, but it can be as follows:
First, the pineal gland is controlled by light, or more precisely, the amount of light perceived by the eye in a day. As in hamsters, 13 hours of darkness per day activates the pineal gland, while for shorter periods of time the pineal gland is not activated, with a balanced transition between activity and inactivity. Light is transmitted from the eye to the suprachiasmatic nucleus of the hypothalamus, and then to the pineal gland, stimulating the pineal gland.
Second, the pineal gland secretes melatonin and several other analogues. Melatonin or another substance thought to enter the bloodstream or through the third ventricle, to the pituitary gland causes a decrease in gonadotropic hormone secretion.
Thus, with the advent of the pineal gland, inhibition of gonadotropic secretion in some animals leads to suppression of the gonads, or even their inactivation. That's probably what happens on winter days when the light intensity is low. After about 4 months of suppression, the inhibition of gonadotropic secretion is broken, the gonads exit inhibition, preparing for an active spring.
Does the pineal gland also have a similar function in controlling sex drive in humans? The answer to this question is still unclear. However, sometimes there is a tumour of the pineal gland, leading to excessive secretion of the pineal hormone, while other types of tumour press on the pineal gland, both types of tumours increase or decrease the function of the pineal gland. genitalia. So perhaps the pineal gland also plays a role in controlling sexual function and fertility in humans.