Stimulation of intra-uterine growth in rat by alpha-melanocyte-stimulating hormone.
We have studied whether endogenous alpha-MSH has a function in stimulating intra-uterine growth in the rat. The approach used was to determine whether or not this hormone is present during the intra-uterine growth spurt, and if binding of endogenous foetal alpha-MSH by antibodies would inhibit this growth. Antibodies against alpha-MSH or ACTH 1-24, either purified or non-purified, induced immunofluorescence in the intermediate lobe of adult male control rats. Using purified anti-alpha-MSH, fluorescence appeared in the foetal intermediate lobe on day 18 of pregnancy, the day that biologically active MSH was first seen. A negative correlation was observed between the pituitary MSH content and foetal body weight only on day 19 of pregnancy. Injection of purified anti-alpha-MSH induced a drop in foetal body weight, but no effect on placental weight was observed. Purified anti-acth 1-24 had no effect upon body weight but caused an increase in placental weight. These results support our previous findings and indicate that endogenous MSH has a function in the stimulation of foetal growth.
D000324:Adrenocorticotropic Hormone / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000302:isolation & purification; D001681:Biological Assay; D001835:Body Weight; D003429:Cross Reactions; D005260:Female; D005333:Fetus / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D005865:Gestational Age; D006128:Growth; D009074:Melanocyte-Stimulating Hormones / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D009929:Organ Size; D010902:Pituitary Gland / Q000032:analysis; D010920:Placenta / Q000032:analysis; D011247:Pregnancy; D051381:Rats
D000906:Antibodies; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones