Nutrient transfer during the reproductive cycle in Glossina austeni Newst.: histology and histochemistry of the milk gland, fat body, and oenocytes

Using thick sections cut from Epon-embedded tissues fixed in Karnovsky's fixative, the cytological changes visible in the light microscope were described for milk gland, fat body and oenocytes during the pregnancy cycle of the female of Glossina austeni. Histochemical procedures on paraffin sections were used to explore changes in nucleic acids, proteins, and tyrosine-containing proteins. The milk gland undergoes a cycle of secretion correlated with the pregnancy cycle and the results are consistent with the view that the protein component of the milk is synthesized in the secretioy cells of the gland. Tyrosine is particularly abundant in the oenocytes which appear to play a crucial role in the metabolism of this amino acid.