The Hormones And Development Of One

’s Sex Essay, Research Paper

The Hormones and Development of One’s Sex

The objectives of this article as I saw them were, (1) to show how fetal gonads

acquire the ability to function as endocrine organs, and (2), to show the

mechanisms by which the endocrine secretions modulate male development. The

researchers went through an extremely extensive explanation of the formation of

the sexual phenotypes by detailing the development of germ cells. They

explained how women’s and men’s gonads appear identical until Leydig cells,

which synthesize testosterone, appear in the connective tissue. This is when

differentiation begins.

The mechanism that this differentiation occurs is as follows. There are two

duct systems which are basically sex specific. In men, Wolffian ducts are

dominant and Mullerian ducts are regressive. Whereas in women it is just the

opposite. Jost believed that the fetal testis secret a hormone which causes such

a differentiation. In order to confirm this belief, he removed the gonads from

embryos, prior to the onset of phenotypic differentiation. All resulted in

female phenotypes. The male phenotype is induced and will not manifest if the

proper secretions are not made from the testis.

Although the article fails to mention how, “Jost deduced that two secretions

from the fetal testis are essential for male development – Mullerian-inhibiting

substance and androgen.” The mechanism in which spermatogenic tubules form

Mullerian-inhibiting substance is still unclear to scientists. Problems with

improper levels of this hormone result in genetic and phenotypic reproductive

disorders.

The other hormone secreted by the testis is testosterone. It has two functions;

it promotes maturation of the spermatogenic tubules (and is therefore indirectly

effecting the levels of Mullerian-inhibiting substance), and it has its well

known essential role in the development of the male genital tract.

Throughout this article there were several areas where it seemed to me, issues

were unresolved, however seemed to me that we have the technology to resolve

them. For instance “The Character of the acceptor sites within the nucleus

(that is, whether protein or DNA) and their number are not resolved.” Couldn’t

one do a radioactive trace or a non-vital stain of some sort to distinguish the

protein from the DNA.

The development of one’s sex is therefore far more than just a genetic decision,

it is (once again) a complex cascade of hormones acting on receptors. These

receptors go on to activate effector molecules which activate target molecules.

If at any point this system is disrupted in any way, one either has the

underdevelopment or incorrect development of the phenotypical gonadal

characteristics.