Studies on the larval salivary gland of Drosophila: I. The nucleic acids

The localization and identification of the two nucleic acids, ribonucleic and desoxyribonucleic, have been determined for the larval salivary gland of Drosophila robusta. The determinations were made by the use of basic staining, Brachet's ribonuclease method, and the Feulgen reaction.The cytological observations suggest that the gland is functional as a secretory organ up to the mid-point of the third instar. It is during this period that the cytoplasmic basophilia (RNA) is most intense. When secretion ceases there is a decided decrease in RNA concentration. These findings suggest that the RNA system is concerned primarily with secretion.     

Studies on salivary gland ribonucleases. II. Purification of ribonucleases from bovine submaxillary gland and the effects of polyamines on their activities.

Four alkaline ribonucleases [EC 3.1.4.22] were purified 2,050- to 3,460-fold from bovine submaxillary gland by repeated CM-Sephadex C-25 chromatography and Sephadex G-50 gel filtration, with a total recovery of about 13%. These were designated as RNase BS1, BS2, BS3, and BS4, based on their order of elution from a CM-Sephadex C-25 column. The molecular weights of these enzymes were estimated by gel filtration to be 19,000, 17,500, 17,000, and 12,000, respectively. These enzymes are very similar to RNase A in that they are inhibited by heparin, show preferential hydrolysis of C5'-O-P linkages adjacent to a cytosine nucleotide rather than a uracil nucleotide, and in their antigenic properties. Spermine was found to stimulate the activities of these enzymes; the degree of stimulation was in the order RNase BS4 greater than BS3 greater than BS2 greater than BS1. The stimulation by spermine is due to the increased cleavage of C5'-O-P linkages adjacent to cytosine nucleotide. The reason for the differences in the degree of spermine stimulation of these enzymes is discussed.     

Influence of submandibular salivary glands on hormone responsiveness of mouse mammary glands

Surgical removal of the submandibular salivary glands (sialoadenectomy) of female Balb/c mice significantly (P less than 0.05) reduced mammary development as judged by development scores and mammae DNA levels. Reduction in mammae development score by sialoadenectomy was observed in both mice saline injected and mice treated with estradiol and progesterone. Autografts of submandibular salivary tissue or daily administration of EGF to sialoadenectomized mice partly alleviated the atrophy of the mammary gland induced by sialoadenectomy (P less than 0.05). The results of our studies are consistent with a model of mammary gland developmental regulation that includes the submandibular salivary gland as a mediator of mammogenesis via secretion of EGF.     

The actions of some putative neurotransmitters on the cockroach salivary gland.

1. Certain putative transmitters were applied to the innervated cockroach salivary gland and their effects on the resting potential and the neurally evoked secretory potential of the acinar cells were observed. 2. gamma-Aminobutyric acid, glutamate, glycine, aspartate and alanine had no significant effect on the resting potential. However, gamma-aminobutyric acid and glutamate reduced the neurally evoked secretory potential but only at concentrations above 10(-3) M3. Acetylcholine and carbachol appeared to act by modifying transmitter output from the salivary nerves. These substances failed to have any effect on the resting potential. 4. The biogenic amines, adrenaline, dopamine, noradrenaline, 5-hydroxy-tryptamine and octopamine, produced hyperpolarizing responses, graded according to concentration. 5. It is suggested that dopamine, the most potent of the biogenic amines tested, is the transmitter at this junction.