The insulinogenic effect of whey protein is partially mediated by a direct effect of amino acids and GIP on β-cells.

BACKGROUND: Whey protein increases postprandial serum insulin levels. This has been associated with increased serum levels of leucine, isoleucine, valine, lysine, threonine and the incretin hormone glucose-dependent insulinotropic polypeptide (GIP). We have examined the effects of these putative mediators of whey's action on insulin secretion from isolated mouse Langerhans islets. METHODS: Mouse pancreatic islets were incubated with serum drawn from healthy individuals after ingestion of carbohydrate equivalent meals of whey protein (whey serum), or white wheat bread (control serum). In addition the effect of individual amino acid combinations on insulin secretion was also tested. Furthermore, the stimulatory effects of whey serum on insulin secretion was tested in vitro in the absence and presence of a GIP receptor antagonist ((Pro(3))GIP[mPEG]). RESULTS: Postprandial amino acids, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) responses were higher after whey compared to white wheat bread. A stimulatory effect on insulin release from isolated islets was observed with serum after whey obtained at 15 min (+87%, P < 0.05) and 30 min (+139%, P < 0.05) postprandially, compared with control serum. The combination of isoleucine, leucine, valine, lysine and threonine exerted strong stimulatory effect on insulin secretion (+270%, P < 0.05), which was further augmented by GIP (+558% compared to that produced by glucose, P < 0.05). The stimulatory action of whey on insulin secretion was reduced by the GIP-receptor antagonist (Pro(3))GIP[mPEG]) at both 15 and 30 min (-56% and -59%, P < 0.05). CONCLUSIONS: Compared with white wheat bread meal, whey causes an increase of postprandial insulin, plasma amino acids, GIP and GLP-1 responses. The in vitro data suggest that whey protein exerts its insulinogenic effect by preferential elevation of the plasma concentrations of certain amino acids, GIP and GLP-1

Extracts of forestry waste greenery and its potential application in bioeconomy

Bakalaura darbā ”Mežsaimniecības atkritumprodukta- skuju ekstraktvielas un to izmantošanas potenciāls bioekonomikā” ietvaros tika apstrādāti 30 paraugi no parasto priežu (Pinus sylvestris L.) un parasto egļu ((Picea abies) skujām, ekstrahējot tos Soksletā dažādos šķīdinātājos, lai iegūtu ekstraktus, kurus turpmāk izmantoja bakalaura darba izstrādē. Darba teorētiskajā daļā tika apkopota zinātniska literatūra par priežu un egļu skujām un ķīmisko sastāvu, tā izmantošanas iespējām Latvijas tirgū un izmantošanu potenciālu bioekonomikas attīstībai. Pētījumā tika izmantota Folina-Šikoltē (Folin- Ciocalteu) un DPPH metode, lai noteiktu polifenolus un antiradikālo aktivitāti. Ekstraktu ķīmiskā sastāvu sīkākai analīzei izmantota GCMS. Bakalaura darba rezultātu sadaļā noteikts optimālākais ekstrahents ekstraktvielu iegūšanā, raksturoti iegūtās ekstraktvielas un to salīdzīnājums. Bakalaura darbs sastāv no 45 lapaspusēm un satur 13 attēlus un 3 tabulas.In the bachelor's thesis“ Extracts of forestry waste greenery and its potential application in bioeconomy” consisted of developing 30 samples of scots pine (Pinus sylvestris L.) and norway spruce (Picea abies), extracting them in soxhlet using different solvents. This was later used in the developement of the bachelor’s thesis. The theoretic part of the work consists of scientific literature about pine and spruce needles and their the chemical composition, aswell its potential to be used for developement of the bioeconomy. The research used the Folin- Ciocalteu and DPPH method, to measure the activity of polyphenols and antiradicals. GC-MS was used to further analyze the chemical composition of the extracts. The results of the bachelor’s thesis determined the most optimal extractants for obtaining the extravagants. The obtained extravagants are listed with their descriptions and their comparisons. The bachelor's thesis consists of 13 pages with 22 illustrations and 3 tabl