A. V. Nalbandov, Ph.D. 



GENETICS of REPRODUCTIVE 

 PHYSIOLOGY 



The scientific literature is replete with examples of heritable differences in 

 reproductive performance between strains or breeds of animals or races of man. Much 

 of this knowledge about hereditary differences in prolificacy had been accumulated 

 before the advent of experimental endocrinology which occurred about 1927. In 

 the infancy of endocrinology the notions concerning the hormonal mechanisms govern- 

 ing reproductive events were vague or incomplete, and it is only relatively recently 

 that a beginning has been made in sorting out the heritable manifestation of hormonal 

 effects and correlate the cause-and-effect relationships between genes and hormones. 



BASIC CONCEPTS OF ENDOCRINOLOGY 



First, agreement is desirable on some of the basic concepts of endocrinology which 

 define the manner in which hormones affect their target tissues. Some of these inter- 

 relations are simple, one-step effects in which a single hormone is known to act directly 

 on its target organ where it produces certain metabolic modifications. Other inter- 

 relations are chain reactions which may involve single hormones as the metabolic 

 modifiers between steps, or, in the more complex relationships, may require a plethora 

 of hormones which may be necessary to produce an exceedingly complex metabolic 

 end result. Both the single-step responses and the complex chain reactions are known 

 to be, or can be presumed to be, under genie control. The importance of genie control 

 may vary depending on the step which is being affected and depending, of course, on 

 the importance of this step in the ultimate metabolic response. 



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