The effect of insulin and relaxin upon mitosis (in vitro) in mammary tissue from pregnant and lactating pigs.
The rate of cellular proliferation in the mammary glands of pigs during late gestation and lactation was assessed by measuring the incorporation of 3H-thymidine (T1) into the DNA of mammary gland explants in vitro. The T1 showed a linear response over the first 9 hr in vitro, and was not affected by the addition of 500 ng insulin/ml medium. From day 100 to parturition the T1 rose, reached a peak at 2 d after parturition and declined during lactation to the lowest levels seen at day 21 of lactation. The inclusion of 0-1000 ng relaxin/ml medium on T1 at 24-72 hr in vitro had no effect in stimulating T1 in mammary tissue explants taken from either pregnant or lactating pigs.
Buttle
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AFRC Institute of Grassland and Environmental Research, HURLEY, Maidenhead, Berks, UK.
Lin
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CL
D000818:Animals; D003470:Culture Media; D046508:Culture Techniques; D005260:Female; D007328:Insulin / Q000494:pharmacology*; D007774:Lactation / Q000187:drug effects / Q000502:physiology; D008321:Mammary Glands, Animal / Q000187:drug effects* / Q000254:growth & development; D008938:Mitosis / Q000187:drug effects; D011247:Pregnancy; D012065:Relaxin / Q000494:pharmacology*; D012098:Reproduction / Q000187:drug effects* / Q000502:physiology; D013552:Swine / Q000254:growth & development*
D003470:Culture Media; D007328:Insulin; D012065:Relaxin