Physiological Differences Associated with Genetic Differences in Egg Production: 1. Organ and Endocrine Gland Weights

Abstract

PHYSIOLOGICAL studies indicate that the pituitary hormones, follicle-stimulating hormone and luteinizing hormone, control follicle growth and ovulation (Sturkie, 1965). Other hormones and physiological substances affect egg production but their effects are generally through effects on general body metabolism (reviewed by Sturkie, 1965). However, there have been very few studies of the physiological nature of genetic differences (especially those produced by selection) in egg production. This is unfortunate since genetic differences provide ideal material for studies of the physiological bases of differences in productive traits. Genetic differences produced by selection can provide large differences to work with, they can be replicated, and the physiological differences detected are likely to be those of most importance, i.e. they provide the same advantages that mutants provide in molecular biology.As organ and endocrine gland weights are generally believed to be indicators of functional and secretory status they provide an ideal starting point for such…